In response, I offer a modest proposal (no children need be consumed): We can not make people accept that the original is better than the homogenized, 'Pottered-up' version; we can not make children like the book better than the film. We can provide the option.
If you feel strongly about this, as I do, then:
1. Get thee to Amazon, or better yet to your friendly local bookseller.
2. Buy a copy of The Dark Is Rising, and any other book that you feel has been ill-served in a recent or forthcoming film version. Try to avoid tie-in editions.
3. In September, take these books to your friendly local junior or secondary school and present them as a gift to be place in school or class libraries.
4. Forward this proposal in any other appropriate journal, community or forum and encourage others to do the same.
Myself I plan to buy a copy of Howls Moving Castle for a start. I haven't seen the Dark is Rising trailer but I have a horrible suspicion that too might be on my list...